U.S. Pat. No. 7,755,123 describes a backside illuminated imaging device in which the thickness of a substrate is reduced to allow a photosensor to easily detect light incident on a back surface. FIG. 7 appended to this specification depicts a backside illuminated imaging device described in FIG. 1C of U.S. Pat. No. 7,755,123. The imaging device described in U.S. Pat. No. 7,755,123 includes a radiation reflector 128 that reflects photons, which are incident on and transmitted through a back surface of a semiconductor device substrate 104 or 104d1 to 104d3, toward a photosensor formed in the semiconductor device substrate.
When radiation reflectors are respectively included in red, green, and blue pixels, for example, some light rays, which are obliquely incident on a color filter of the green pixel and are transmitted through the color filter, may be reflected by the radiation reflector of the blue pixel, and may be incident on the photosensor of the blue pixel. In this case, mixture of colors may occur between the green and blue pixels. Likewise, mixture of colors may occur between the green and blue pixels.